The invention relates to a dose unit for a dry powder inhaler comprising:                a dose carrier including a plurality of pockets each adapted to contain a dose of medication powder suitable for inhalation, said pockets being sequentially arranged such that the content of the pockets can be sequentially exposed to a flow of air for successive inhalations and        a plurality of medication powder doses arranged in pockets of the dose carrier.        
Typically, all pockets of such dose units contain a medication dose including a blend of at least one pharmaceutically active ingredient and at least one excipient. It has already been proposed to use a pair of such dose units in the same inhaler and more specifically to provide inhalers adapted to deliver medication powders from both units simultaneously. Such embodiments are for example described in WO 2005/002654 and WO 2004/011070. In particular embodiments known from such references, the first dose unit contains a first medication powder and the second dose unit contains a second medication powder different from the first one, whereby the inhaler can be used to deliver a combination of pharmaceutically active ingredients stored in separate carriers. This is of particular interest in certain therapies, for administering to the patient pharmaceutically active ingredients which must be delivered in combination but stored separately for stability reasons.
However, it might be desirable to administer to the patient not only the combination of the two medication powders but also, alternatively, only one of the two medication powders, in case the two medications must be administered at a different frequency. For example, it might be desirable to administer the first medication powder four times a day (QID) and the second medication powder twice in a day (BID).
With the known dose units and associated inhalers, this cannot be achieved with a single inhaler and the patient would rather have to alternatively use a first inhaler to inhale the first medication powder and a second inhaler to inhale the combination of the first and second medication powders.
This method is not only inconvenient but also confusing for the patient, whereby it may increase the risk of incorrect dosing.
It is an object of the invention to solve the aforementioned problem and allow the delivery of a plurality of inhalable drugs for combined treatments at different frequencies by means of a single inhalation device.